TWI577124B - Multi-output power converter - Google Patents

Description

Multiple output power converter

The present invention relates to a switched power converter, and more particularly to a multiple output power converter.

A switched power converter is an electronic device that converts the power of an input power converter to a desired output power source by switching a switch in the power converter. Common switched power converters include boost converters, buck converters, flyback converters, and the like. However, the conventional multi-output switching power converter not only generates switching loss when switching, but also causes electromagnetic interference (EMI) caused by the surge, resulting in poor power conversion efficiency and dynamic output response.

Accordingly, it is an object of the present invention to provide a multi-output power converter with good efficiency and dynamic output response.

The technical means for solving the problem of the prior art is to provide a multi-output power converter connected to an input power source, the multi-output power converter comprising: a storage inductor, a first end of which is electrically connected a positive terminal of the input power source; a main switch electrically connected to the energy storage a second end of the inductor and a negative terminal of the input power; an active buffer circuit having a first transformer and an auxiliary switch, wherein a primary side first end of the first transformer is electrically connected to the energy storage The second end of the first transformer is electrically connected to the negative end of the input power source, and the auxiliary switch is electrically connected to a primary side second end of the first transformer a first output unit electrically connected in parallel between a secondary side first end of the first transformer and the secondary side second end for outputting to a first An output load; an energy transfer capacitor having a first end electrically connected to the first side first end of the first transformer; and a second transformer having a primary side first end electrically connected to the energy transfer capacitor a second end, one primary side second end is electrically connected to the negative power end of the input power source; a second output unit is electrically connected to a secondary side first end of the second transformer and the input power source Between the negative terminals, Output to a second output load; and between the second terminal and the negative power supply input terminal of a third output unit electrically connected to the energy transfer capacitor, a third output for outputting to the load.

In an embodiment of the invention, a multi-output power converter is provided. The first output unit has a first rectifying diode and a first filter capacitor. An anode end of the first rectifying diode is electrically connected. The first filter capacitor is electrically connected between a cathode end of the first rectifying diode and the negative terminal of the input power source, and is provided for the first end of the first transformer The output loads are connected in parallel.

In an embodiment of the invention, a multi-output power converter is provided. The second output unit has a second rectifying diode and a second filter capacitor. An anode end of the second rectifying diode is electrically connected. The second filter capacitor is electrically connected between a cathode end of the second rectifying diode and the negative end of the input power source, and is provided to the second end of the second transformer. The output loads are connected in parallel.

In an embodiment of the invention, a multi-output power converter is provided. The third output unit has a third rectifying diode and a third filter capacitor. An anode end of the third rectifying diode is electrically connected. The third filter capacitor is electrically connected between a cathode end of the third rectifying diode and the negative terminal of the input power source, and is connected to the third output load in parallel at the second end of the energy transfer capacitor .

In an embodiment of the present invention, a multi-output power converter is provided. The main switch is a gold-oxygen half field effect transistor, and the drain of the metal oxide half field effect transistor is electrically connected to the energy storage inductor. At the two ends, the source of the MOS field-effect transistor is electrically connected to the negative terminal of the input power source.

In an embodiment of the present invention, a multi-output power converter is provided. The auxiliary switch is a metal oxide half field effect transistor, and the drain of the metal oxide half field effect transistor is electrically connected to the first transformer. At the two ends, the source of the MOS field-effect transistor is electrically connected to the negative terminal of the input power source.

The circuit architecture adopted by the multi-output power converter of the present invention is mainly composed of a single-ended primary inductance converter (SEPIC), and can be single by providing a first transformer and a second transformer. An input power supply provides multiple sets of output voltages for a wider range of applications. In addition, the first transformer and the auxiliary switch are used to form an active buffer, so that the main switch has a zero voltage switching characteristic when the high frequency switching transient is turned on; and the auxiliary switch also has zero when the high frequency switching transient is turned on. The characteristics of voltage switching can reduce the switching loss and electromagnetic interference generated by the main switch and the auxiliary switch under high frequency switching, and the multi-output power converter of the present invention has good power conversion efficiency and dynamic output response.

100‧‧‧Multiple output power converter

1‧‧‧Active snubber circuit

2‧‧‧First output unit

3‧‧‧Second output unit

4‧‧‧ third output unit

C _a ‧‧‧ energy transfer capacitor

C _O1 ‧‧‧First Filter Capacitor

C _O2 ‧‧‧Second filter capacitor

C _O3 ‧‧‧third filter capacitor

C _S1 ‧‧‧Parasitic capacitance

C _S2 ‧‧‧Parasitic capacitance

D ₁ ‧‧‧First Rectifier Diode

D ₂ ‧‧‧Secondary rectifier

D ₃ ‧‧‧3rd rectifying diode

D _S1 ‧‧‧ Parasitic diode

D _S2 ‧‧‧ Parasitic diode

I ₁ ‧‧‧ Current

I ₂ ‧‧‧current

I _S2 ‧‧‧ Current

L _a ‧‧‧ storage inductor

L _m1 ‧‧‧Magnetic inductance

L _m2 ‧‧‧magnetized inductor

O ₁ ‧‧‧first output load

O ₂ ‧‧‧second output load

O ₃ ‧‧‧ third output load

S ₁ ‧‧‧ main switch

S ₂ ‧‧‧Auxiliary switch

T _r1 ‧‧‧First transformer

T _r2 ‧‧‧second transformer

V _s ‧‧‧Input power supply

1 is a circuit diagram showing a multi-output power converter according to an embodiment of the present invention; [FIG. 2] is a circuit diagram showing a multi-output power converter according to an embodiment of the present invention; 3] is a circuit diagram showing a multi-output power converter in an operation mode 1 according to an embodiment of the present invention; [Fig. 4] is a circuit showing a multi-output power converter in an operation mode 2 according to an embodiment of the present invention Figure 5 is a circuit diagram showing a multi-output power converter in operation mode 3 according to an embodiment of the present invention; [Fig. 6] is a view showing a multi-output power converter in operation according to an embodiment of the present invention Circuit diagram of mode four; [Fig. 7] is a circuit diagram showing a multi-output power converter in operation mode 5 according to an embodiment of the present invention; [Fig. 8] is a diagram showing a multi-output power supply according to an embodiment of the present invention. Circuit diagram of the converter in the operating mode 6; [Fig. 9] is a circuit diagram showing the multi-output power converter in the operating mode VII according to the embodiment of the present invention

Hereinafter, embodiments of the present invention will be described with reference to Figs. 1 to 9 . This description is not intended to limit the embodiments of the invention, but is an embodiment of the invention.

As shown in FIG. 1 , a multi-output power converter 100 according to an embodiment of the present invention is connected to an input power source V _s , and the multi-output power converter 100 includes: a storage inductor L _a , a first The terminal is electrically connected to a positive terminal of the input power source V _s ; a main switch S _{1 is} electrically connected between a second end of the energy storage inductor L _a and a negative terminal of the input power source V _s ; The circuit 1 has a first transformer _Tr1 and an auxiliary switch S2. A primary side first end of the first transformer _Tr1 is electrically connected to the second end of the energy storage inductor La, and _a second of the first transformer _Tr1 The second side of the secondary side is electrically connected to the negative terminal of the input power source V _s , and the auxiliary switch S _{2 is} electrically connected between a primary side second end of the first transformer _Tr1 and a negative terminal of the input power source V _s ; An output unit 2 is electrically connected in parallel between a secondary side first end and a second side second end of the first transformer T _r1 for outputting to a first output load O ₁ ; an energy transfer capacitor C _a , the primary side of a first end thereof connected to the first terminal of the first transformer T _r1; a second transformer T _{r 2} , a first side of the primary side is electrically connected to a second end of the energy transfer capacitor C _a , and a primary side second end is electrically connected to the negative power end of the input power source V _s ; a second output unit 3 is electrically connected between the secondary side of a transformer T _r2 of the second terminal and a negative electrical terminal of a first power source V _s is input, for outputting a second output load to the O _2; and a third output unit 4 electrically The second end connected to the energy transfer capacitor C _a is connected to the negative terminal of the input power source V _s for outputting to a third output load O ₃ .

The active snubber circuit 1 formed by the first transformer _Tr1 and the auxiliary switch S ₂ causes the main switch S _{1 to} have a zero-voltage switching (ZVS) characteristic when the high-frequency switching transient is turned on, and also assists The switch S ₂ has a characteristic of zero voltage switching when the high frequency switching transient is turned on. Therefore, the switching loss and EMI generated by the main switch S ₁ and the auxiliary switch S ₂ under high frequency switching can be effectively reduced, the life of the used components is prolonged, and the multi-output power converter of the present invention has good efficiency. Response with dynamic output.

In the circuit architecture, the input power source V _s is a single power supply, and the first output unit 2, the second output unit 3, and the third output unit 4 each have a diode and a filter capacitor for rectification and filtering. . Of course, the filter capacitor can be replaced with other filter circuits for filtering. With the above structure, by a first transformer and a second transformer T _r1 T _r2, a single input power supply capable of providing multiple sets of V _s output voltage, it has a broader range of use.

2 is an equivalent circuit diagram of FIG. 1. As shown in FIG. 2, according to the multi-output power converter 100 of the embodiment of the present invention, the diode and the filter capacitor of the first output unit 2 are respectively the first rectification. The diode D ₁ and the first filter capacitor C _O1 , an anode terminal of the first rectifier diode D ₁ is electrically connected to the second side first end of the first transformer T _r1 , and the first filter capacitor C _{O1 is} electrically connected A cathode end of the first rectifying diode D ₁ is connected to a negative terminal of the input power source V _s and is connected in parallel to the first output load O ₁ . The diode and the filter capacitor of the second output unit 3 are respectively a second rectifying diode D ₂ and a second filter capacitor C _O2 , and an anode end of the second rectifying diode D ₂ is electrically connected to the second transformer T _r2 The second side of the secondary side, the second filter capacitor C _{O2 is} electrically connected between a cathode end of the second rectifying diode D _{2 and} the negative terminal of the input power source V _s , and is connected in parallel with the second output load O _{2 .} . The diode and the filter capacitor of the third output unit 4 are respectively a third rectifying diode D ₃ and a third filter capacitor C _O3 , and an anode end of the third rectifying diode D ₃ is electrically connected to the second transformer _Tr2 The first side of the secondary side, the third filter capacitor C _{O3 is} electrically connected between a cathode end of the third rectifying diode D _{3 and} the negative terminal of the input power source V _s , and is connected in parallel to the third output load O _{3 .} .

As shown in Fig. 2, in the equivalent circuit of the first transformer _Tr1 and the second transformer _Tr2 , a magnetizing inductance L _m1 and L _m2 are respectively provided on the primary side. The polarity of the first transformer T _r1 and the second transformer T _r2 may be a polarity or a polarity reduction. In this embodiment, the first transformer T _r1 is a polarity and the second transformer T _r2 is a polarity reduction. By changing the first transformer and the second transformer T _r1 T _r2 ratio of the respective primary side and the secondary side voltage of the first output load change O _1, O _2, and a second output load third output O ₃ of the load The ratio of the output voltage is varied to provide a plurality of sets of output voltages, and the multi-output power converter 100 of the present invention can have an output characteristic of up/down, and has a wider range of use.

As shown in FIGS. 1 and 2, according to the multi-output power converter 100 of the embodiment of the present invention, the main switch S ₁ may be a MOSFET or a bipolar junction transistor (BJT). ) or insulated gate bipolar transistor (IGBT). In the present embodiment, the main switch S ₁ is an N-type the MOSFET, a parasitic diode D _S1, and a parasitic capacitance C _S1, the main switch S parasitic diode ₁ D _S1 is formed between the drain and source And the parasitic capacitance C _{S1 is} parallel to each other, the drain of the gold-oxygen half field effect transistor is electrically connected to the second end of the energy storage inductor L _a , and the source of the gold oxygen half field effect transistor is electrically connected to the input power source V _s Negative terminal.

Similarly, the auxiliary switch S ₂ may be a MOS field effect transistor, a bipolar junction transistor, or an insulated gate bipolar transistor. In the present embodiment, the auxiliary switch S ₂ is an N-type MOSFET, _S2 A parasitic diode D _S2 and a parasitic capacitance C _S2, the auxiliary switch S parasitic ₂ of diode D between the drain and source And the parasitic capacitance C _{S2 is} parallel to each other, the drain of the gold oxide half field effect transistor is electrically connected to the second end of the first transformer T _r1 , and the source of the gold oxygen half field effect transistor is electrically connected to the input power source V _s Negative terminal.

A controller (not shown) is electrically connected to the main switch S ₁ and the auxiliary switch S ₂ to control the on or off of the main switch S ₁ and the auxiliary switch S ₂ . In this embodiment, the controller is electrically connected to the gate of the main switch S _{1 and} the gate of the auxiliary switch S ₂ .

3 to 9 are a complete switching cycle of the multi-output power converter 100 of the embodiment of the present invention, which is divided into seven consecutive operating modes depending on the state of each component. Among them, the solid line circuit represents the path, the dotted line circuit represents the open circuit, and the dotted arrow indicates the current direction. Various operating modes as follows: As shown in FIG. 3, during operation in a mode of main switch S ₁ is turned on and the auxiliary switch S ₂ is off; the input current I ₁ from the power source V _s electropositive end of the inductor flowing L _a flows back to the negative terminal of the input power source V _s with the main switch S ₁ ; the energy transfer capacitor C _a starts to discharge, and the discharge current I ₂ flows through the main switch S ₁ , the magnetization of the energy transfer capacitor C _a and the second transformer T _r2 The inductance L _m2 , the magnetizing inductance L _{m2 of the} second transformer T _r2 starts to store energy; the magnetizing inductance L _m1 energy stored in the first transformer T _r1 is coupled to the secondary side so that the second rectifying diode D ₂ is forwarded And releasing energy to the second output load O ₂ , the energy of the first filter capacitor C _O1 starts to be released to the first output load O ₁ , and the power required by the third output load O ₃ is obtained by the third filter capacitor C _O3 provide.

As shown in FIG. 4, during operation of mode two, the main switch S ₁ is off and the auxiliary switch is continuing to cut off the S _2, I ₁ current begins charging energy transfer capacitor C _a, and via a third rectifier diode D ₃ is turned on to provide power to a load third output O _3. The second transformer T _r2 transfers the stop energy from the primary side winding to the secondary side winding; and the magnetizing inductance L _{m2 of the} second transformer T _r2 begins to release energy via the primary side winding to the secondary side winding and via the second rectification The diode D _{2 is} delivered to a second output load O ₂ . Further, stored in the first magnetizing inductance of the transformer T _r1 L _m1 energy continues through the primary winding is transferred to the secondary winding, and rectified via a first diode D ₁ is transmitted to a first load output O _1.

As shown in FIG. 5, during three operating modes, the main switch S ₁ is off and the duration of the auxiliary switch S ₂ is turned on; a first transformer T _r1 due to the action of the magnetizing inductance L _m1, flowing through the magnetizing inductance L _m1 The current rise rate (di/dt) is limited, so the auxiliary switch S ₂ is turned on in a state of zero voltage switching. In this mode of operation, the current I ₁ is divided into two parts: one part is the current I _S2 , the energy storage of the magnetizing inductance L _m1 of the first transformer T _{r1 is} started via the auxiliary switch S ₂ ; the other part is the current I ₂ , and the energy transfer continues. charging the capacitor C _a, and through the third rectifying diode D ₃ to provide power to the load third output O _3. At this time, the second transformer T _r2 magnetizing inductance L _m2 continue to release energy transfer via the primary winding to the secondary winding, via a second rectifier diode D ₂ is transmitted to the second load output O _2, and a first output The power required for load O ₁ is then provided by the first filter capacitor C _O1 .

When current I ₁ = current I _S2 , it enters mode four. As shown in FIG. 6, during operation of Mode 4, the main switch S ₁ is off and the duration of the auxiliary switch S ₂ is turned on continuously; At this time, the current flowing through the auxiliary switch S _S2 = current I ₂ of the current I ₁ + I _2; C _a energy transfer capacitor begins to discharge through the discharge current path I ₂ T _r1 of the first transformer magnetizing inductance L _m1, the second auxiliary switch S ₂ to the magnetizing inductance of the transformer T _r2 L _m2. At this time, the power required by the first output load O ₁ continues to be provided by the first smoothing capacitor C _O1 , and the power required by the second output load O ₂ is provided by the second smoothing capacitor C _O2 , and the third output The power required to load O ₃ is then provided by the third filter capacitor C _O3 .

As shown, during operation of the Model 5, continuing to the main switch S ₁ is off and the auxiliary switch S ₂ is turned on continuously to FIG. 7, when the current I ₁ <current _S2, the parasitic capacitance of the main switch S C _{S1 1} start I Is discharged. At this time, the power required by the first output load O ₁ continues to be provided by the first filter capacitor C _O1 , and the power required by the second output load O ₂ continues to be provided by the second filter capacitor C _O2 , and the third The power required to output the load O ₃ continues to be provided by the third filter capacitor C _O3 .

As shown in Figure 8, during the six operating mode, the main switch S ₁ is off and the duration of the auxiliary switch S ₂ is turned on continuously; _S1 when the voltage of the parasitic capacitance of the main switch S ₁ is C is discharged to zero, the main switch S ₁ is The parasitic diode D _S1 begins to conduct, causing the main switch S ₁ to have a zero voltage switching characteristic when the switch is turned on. At this time, the power required by the first output load O ₁ continues to be provided by the first filter capacitor C _O1 , and the power required by the second output load O ₂ continues to be provided by the second filter capacitor C _O2 , and the third The power required to output the load O ₃ continues to be provided by the third filter capacitor C _O3 .

₁ a first desired power output will continue to be O load provided by a first filter capacitor C _O1,; as shown in FIG. 9, the operation mode during the seven main switch S ₁ is turned on and the auxiliary switch S ₂ is turned on for the duration The power required for the second output load O ₂ continues to be provided by the second filter capacitor C _O2 , and the power required for the third output load O ₃ continues to be provided by the third filter capacitor C _O3 . When the auxiliary switch S ₂ is turned off, the operating mode of a complete switching cycle of the power converter is completed. When the auxiliary switch S ₂ is turned off, a complete switching cycle is completed.

The above description and description are only illustrative of the preferred embodiments of the present invention, and those of ordinary skill in the art can make other modifications in accordance with the scope of the invention as defined below and the description above, but such modifications should still be It is within the scope of the invention to the invention of the invention.

100‧‧‧Multiple output power converter

1‧‧‧Active snubber circuit

2‧‧‧First output unit

3‧‧‧Second output unit

4‧‧‧ third output unit

C _a ‧‧‧ energy transfer capacitor

L _a ‧‧‧ storage inductor

O ₁ ‧‧‧first output load

O ₂ ‧‧‧second output load

O ₃ ‧‧‧ third output load

S ₁ ‧‧‧ main switch

S ₂ ‧‧‧Auxiliary switch

T _r1 ‧‧‧First transformer

T _r2 ‧‧‧second transformer

V _s ‧‧‧Input power supply

Claims (6)

A multi-output power converter is connected to an input power supply, the multi-output power converter comprises: a storage inductor, a first end of which is electrically connected to a positive terminal of the input power; a main switch, electrical Connected between a second end of the energy storage inductor and a negative terminal of the input power; an active buffer circuit having a first transformer and an auxiliary switch, a primary side first end of the first transformer Connected to the second end of the energy storage inductor, a secondary side second end of the first transformer is electrically connected to the negative end of the input power source, and the auxiliary switch is electrically connected to the first one of the first transformer a second output end is electrically connected in parallel between a second side first end of the first transformer and the second side of the second side. Outputting to a first output load O ₁ ; an energy transfer capacitor having a first end electrically connected to the primary side first end of the first transformer; a second transformer having a primary side first end electrical property Connected to the energy transfer capacitor a second end of the first end of the second transformer is electrically connected to the second end of the second transformer and the input is electrically connected to the negative end of the input power source; Between the negative terminals of the power source for outputting to a second output load; and a third output unit electrically connected between the second end of the energy transfer capacitor and the negative terminal of the input power source, To output to a third output load. The multi-output power converter of claim 1, wherein the first output unit has a first rectifying diode and a first filter capacitor, and an anode terminal of the first rectifying diode is electrically connected to the a first side of the second side of the first transformer, the first filter capacitor is electrically connected to the first A cathode end of the first rectifier diode is coupled to the negative terminal of the input power source and is coupled in parallel with the first output load. The multi-output power converter of claim 1, wherein the second output unit has a second rectifying diode and a second filter capacitor, and an anode terminal of the second rectifying diode is electrically connected to the second rectifying diode a second side first end of the second transformer, the second filter capacitor is electrically connected between a cathode end of the second rectifying diode and the negative end of the input power source, and is provided for the second output load in parallel. The multi-output power converter of claim 1, wherein the third output unit has a third rectifying diode and a third filter capacitor, and an anode terminal of the third rectifying diode is electrically connected to the third rectifying diode The second filter capacitor is electrically connected between a cathode end of the third rectifying diode and the negative terminal of the input power source, and is connected in parallel with the third output load. The multi-output power converter of claim 1, wherein the main switch is a metal oxide half field effect transistor, and the drain of the metal oxide half field effect transistor is electrically connected to the second end of the energy storage inductor. The source of the MOS field effect transistor is electrically connected to the negative terminal of the input power source. The multi-output power converter of claim 1, wherein the auxiliary switch is a metal oxide half field effect transistor, and the drain of the metal oxide half field effect transistor is electrically connected to the second end of the first transformer. The source of the MOS field effect transistor is electrically connected to the negative terminal of the input power source.